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perf offcpu: Accept allowed sample types only 

As offcpu-time event is synthesized at the end, it could not get the
all the sample info.  Define OFFCPU_SAMPLE_TYPES for allowed ones and
mask out others in evsel__config() to prevent parse errors.

Because perf sample parsing assumes a specific ordering with the
sample types, setting unsupported one would make it fail to read
data like perf record -d/--data.

Fixes: edc41a1099 ("perf record: Enable off-cpu analysis with BPF")
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Blake Jones <blakejones@google.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Milian Wolff <milian.wolff@kdab.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: bpf@vger.kernel.org
Link: http://lore.kernel.org/lkml/20220624231313.367909-3-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Namhyung Kim 2022-06-24 16:13:09 -07:00 committed by Arnaldo Carvalho de Melo
parent d6838ec44b
commit 49c692b7df
3 changed files with 24 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
tools/perf/util/bpf_off_cpu.c
View File

@ -265,6 +265,12 @@ int off_cpu_write(struct perf_session *session)
sample_type = evsel->core.attr.sample_type;
if (sample_type & ~OFFCPU_SAMPLE_TYPES) {
pr_err("not supported sample type: %llx\n",
(unsigned long long)sample_type);
return -1;
}
if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER)) {
if (evsel->core.id)
sid = evsel->core.id[0];
@ -319,7 +325,6 @@ int off_cpu_write(struct perf_session *session)
}
if (sample_type & PERF_SAMPLE_CGROUP)
data.array[n++] = key.cgroup_id;
/* TODO: handle more sample types */
size = n * sizeof(u64);
data.hdr.size = size;

9
tools/perf/util/evsel.c
View File

@ -48,6 +48,7 @@
#include "util.h"
#include "hashmap.h"
#include "pmu-hybrid.h"
#include "off_cpu.h"
#include "../perf-sys.h"
#include "util/parse-branch-options.h"
#include <internal/xyarray.h>
@ -1102,6 +1103,11 @@ static void evsel__set_default_freq_period(struct record_opts *opts,
}
}
static bool evsel__is_offcpu_event(struct evsel *evsel)
{
return evsel__is_bpf_output(evsel) && !strcmp(evsel->name, OFFCPU_EVENT);
}
/*
* The enable_on_exec/disabled value strategy:
*
@ -1366,6 +1372,9 @@ void evsel__config(struct evsel *evsel, struct record_opts *opts,
*/
if (evsel__is_dummy_event(evsel))
evsel__reset_sample_bit(evsel, BRANCH_STACK);
if (evsel__is_offcpu_event(evsel))
evsel->core.attr.sample_type &= OFFCPU_SAMPLE_TYPES;
}
int evsel__set_filter(struct evsel *evsel, const char *filter)

9
tools/perf/util/off_cpu.h
View File

@ -1,6 +1,8 @@
#ifndef PERF_UTIL_OFF_CPU_H
#define PERF_UTIL_OFF_CPU_H
#include <linux/perf_event.h>
struct evlist;
struct target;
struct perf_session;
@ -8,6 +10,13 @@ struct record_opts;
#define OFFCPU_EVENT "offcpu-time"
#define OFFCPU_SAMPLE_TYPES (PERF_SAMPLE_IDENTIFIER | PERF_SAMPLE_IP | \
PERF_SAMPLE_TID | PERF_SAMPLE_TIME | \
PERF_SAMPLE_ID | PERF_SAMPLE_CPU | \
PERF_SAMPLE_PERIOD | PERF_SAMPLE_CALLCHAIN | \
PERF_SAMPLE_CGROUP)
#ifdef HAVE_BPF_SKEL
int off_cpu_prepare(struct evlist *evlist, struct target *target,
struct record_opts *opts);